Chapter 10: Migration and Navigation Flashcards
Migration allows birds to…
exploid predictable seasonal feeding opportunities while living in favorable climates throughout the year
Migration can be ___ (up and down mountain slopes from summer to winter) or _______ (from Arctiv to southern tips of Africa).
local
long-distance
Migration differs from nomadic wandering by…
following predicable, seasonal opportunities
nomatic wandering is unpredictable and aseasonal
Example of nomadic wanderer bird
Red crossbill, fruit and nectar eaters in the tropics
In North America, migration is typically a _____ orientation due to…
north-south
coastlines, major rivers, and mountain ranges are typically north-south
In Europe, migraton is initially _____ in orientation (at least initially before becoming ____) due to…
east-west, north-south
the posotion of the Alps and the Mediterranean Sea
Major migration routes are called
flyways
____ species don’t migrate as far noth in their winter as species in the northern hemisphere migrate south in their winter.
southern
Differential migration is…
when birds of different age or sex migrate for different differences.
Example for differential migration
The Dark-eyed Junco.
Young males winter at latitude of Ohio and Indiana,
Adult males winter in Kentucky and Virginia
Young females just south of adult males
Adult females along the Gulf of Mexico
It is thought that young birds don’t migrate as far as adults because their _____ during migration is greater, therefore there has been selection for shorter migrations in
young birds…
mortality
Males tend not to travel as far south as females because…
there is an advantage for them to return early in the spring to establish territories
Adult females are pushed furthest south to…
avoid competition with the other age/sex classes.
Blackcaps that winter in England exhibit an innate orientation to the northwest, suggesting…
a rapid evolution of the genetic program that controls their migratory behavior.
What are the disadvantages of migration?
- increased energy expenditure
- Increased risk of depredation
- Requirement of radical physiological adjustments
What bird breeds in the fall so it can feed its nestlings migrants trying to cross the Mediterranean Sea?
Eleonora’s Falcon
Only about ___ of small landbirds live through round-trip migration
1/2
What are the two hypotheses as to why birds migrate?
A.) Escape from inhospitable climates. Suggests that migrants are temperate-zone birds that move to the tropics in the winter
B.) Exploitation of seasonal feeding opportunities. Migrants were originally tropical birds that started to move to northern areas during the summer.
Hummingbirds, tanagers, North American warblers, and tyrant flycatchers all fit this description
Arctic Terns migrate _____ round trip every year
25,000 km
Blackpoll Warblers fly for ___-___ hours over the _____Ocean from the E ____ to NE ____
80-90 hours, Atlantic Ocean, E US, NW SA
For many birds, they lose about ___% of body weight per hour of flight
0.9%
Birds have enough energy for about ___ hours or ___ km of flight
100 hours, 2500km
Hummingbirds can go about -___ km and for ___ hours
1000 km and 26 hours
Many birds, such as ____ and ___ will actually double their weight before migration
Blackpoll Warblers and Ruby-Throated Hummingbirds
Fat makes up ___% of small, nonmigrating birds but increases to ___% prior to migration in short-range and ___% prior to migration in long0range migrants
3-5% non-migratory
13-25% short-range
30-47% long-range
Songbirds will fly for ___ days straight and stop to increase fat reserves again
1-3 days
Shorebirds tend to fly for a few days and then stop for extended periods at kkey staging areas called…
stopover sites
Example of stopover site
In Delaware Bay area, crabs lay eggs right around shorebird migration. Shorebirds stop here to feed on the eggs of crabs
Zugenruhe
The inherent rhythm to migration leading to migratory restlessness
Emlen Funnel
Used to observe Zugenruhe. Birds are on an inkpad to observe what direction the bird is trying to go
Although daylength triggers internal changes that allow for migration, birds will wait for…
favorable weather conditions (want tailwinds rather than to fly into wind)
Male Red-Winged Blackbirds will arrive on the breeding ground ___ weeks before the females
1-5 weeks
In the Least Flycatcher, offspring migrate south ___ than parents.
earlier
In most shorebirds, parents will migrate up to one month ___ than offspring
earlier
What kind of birds migrate during the day?
- Hawks (warm air currents)
- Swifts and swallows (eat on the wing)
Why do small landbirds fly at night?
a) avoid predators
b) weather conditions are usually more calm at night, less likley to meet head winds
How do birds navigate?
- visual landmarks
- solar compass
- stellar compass
- olfactory cues
- geomagnatic fields
Due to their solar compass, hoing pigeons perform better on ____ days than on ___ cloudy days
sunny, cloudy
Captive European Starlings will orient their Zugenruhe ______ when the sun is visible but the activity becomes ____ when the sun is not present.
in the proper direction , scattered
To use the sun, birds must understand
the changing position of the sun (about 15 degrees per hour)
Indigo Bunting use the constellation that are within ___ degrees of the _____.
35 degrees of the North Star
Indigo Buntings are familiar with what constillations? What is the significance of this?
Big Dipper, Little Dipper, Draco, Cepheus, and Cassiopeia.
If part oft eh sky is cloudy, they can use what is visible to guide them.
